In biology, evolution is the change in heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation tends to exist within any given population as a result of genetic mutation and recombination. Evolution occurs when evolutionary processes such as natural selection...

In biology, evolution is the change in heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation tends to exist within any given population as a result of genetic mutation and recombination. Evolution occurs when evolutionary processes such as natural selection...

In biology, evolution is the change in heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation tends to exist within any given population as a result of genetic mutation and recombination. Evolution occurs when evolutionary processes such as natural selection...

In biology, evolution is the change in heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation tends to exist within any given population as a result of genetic mutation and recombination. Evolution occurs when evolutionary processes such as natural selection...

In biology, evolution is the change in heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation tends to exist within any given population as a result of genetic mutation and recombination. Evolution occurs when evolutionary processes such as natural selection...

In crystallography, the cubic (or isometric) crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals. There are three main varieties of these crystals: Primitive cubic (abbreviated cP and alternatively called simple cubic) Body-centered cubic (abbreviated cI or bcc) Face-centered cubic (abbreviated cF or fcc)Note: the term fcc is often used in synonym for the cubic close-packed or ccp structure occurring in metals. However, fcc stands for a face-centered-cubic Bravais lattice, which is not necessarily close-packed when a motif is set onto the lattice points. E.g. the diamond and the zincblende lattices are fcc but not close-packed. Each is subdivided into other variants listed below. Although the unit cells in these crystals are conventionally taken to be cubes, the primitive unit cells often are not. Bravais lattices The three Bravais lattices in...

The Boar's Head Society (1910 – 1970s) was a student conversazione society devoted to poetry at Columbia University. It was an "adjunct to Columbia College's Philolexian Society... The purpose of their new society was entirely creative: reading and commenting on each other's works." History John Erskine, English professor, formed the society. This connected the society through him to Columbia's student literary magazine, The Morningside Review (founded first as the Literary Monthly in 1815, renamed by Erskine in 1898, and renamed the Columbia Review in 1932). In 1931, it claimed to be the only organization on campus "devoted exclusively to poetry."The society seems to have started during the 1909–1910 academic schoolyear, as in November 1909 it sponsored theatrical productions of Shakespeare's Comedy of Errors and Oscar Wilde's An Ideal Husband. Competitions The society also held annual literary competitions and then published winners in the magazine. Competition judges included William Carlos Williams...

Gamelan () (Javanese: ꦒꦩꦼꦭꦤ꧀, Sundanese: ᮌᮙᮨᮜᮔ᮪, Balinese: ᬕᬫᭂᬮᬦ᭄) is the traditional ensemble music of the Javanese, Sundanese, and Balinese peoples of Indonesia, made up predominantly of percussive instruments. The most common instruments used are metallophones played by mallets and a set of hand-played drums called kendhang/Kendang, which register the beat. The kemanak (a banana-shaped idiophone) and gangsa (another metallophone) are commonly used gamelan instruments in Bali. Other...

Ra (; Ancient Egyptian: rꜥ; also transliterated rꜥw /ˈɾiːʕuw/; cuneiform: 𒊑𒀀 ri-a or 𒊑𒅀ri-ia; Phoenician: 𐤓𐤏, romanized: rʿ) or Re (; Coptic: ⲣⲏ, romanized: Rē) was the ancient Egyptian deity of the sun. By the Fifth Dynasty, in the 25th and 24th centuries BC, he had become one of the most important gods in ancient Egyptian religion, identified primarily with the noon-day sun. Ra ruled in all parts of the created world: the sky, the earth, and the underworld. He was the god of the sun, order, kings and the sky. Ra was portrayed as a falcon and shared characteristics with the sky-god Horus. At times the two deities were merged as Ra-Horakhty, "Ra, who is...

A power MOSFET is a specific type of metal–oxide–semiconductor field-effect transistor (MOSFET) designed to handle significant power levels. Compared to the other power semiconductor devices, such as an insulated-gate bipolar transistor (IGBT) or a thyristor, its main advantages are high switching speed and good efficiency at low voltages. It shares with the IGBT an isolated gate that makes it easy to drive. They can be subject to low gain, sometimes to a degree that the gate voltage needs to be higher than the voltage under control. The design of power MOSFETs was made possible by the evolution of MOSFET and CMOS technology, used for manufacturing integrated circuits since the 1960s. The power MOSFET shares its operating principle with its low-power counterpart, the lateral MOSFET. The power MOSFET, which is commonly used in power electronics, was adapted from the standard MOSFET and commercially introduced in the 1970s.The power MOSFET is the most common power semiconductor device in the world, due to its low gate drive power, fast switching speed, easy advanced paralleling capability, wide bandwidth, ruggedness, easy drive, simple biasing, ease of application...